JPH0898812A - Fundus camera - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to align the corneal reflections even during magnified imaging. The light fluxes from the alignment light sources 13 to 16 are reflected by the light splitting member 2 and are condensed by the objective lens 1 between the corneal curvature center and the corneal apex, respectively, and these reflected lights are reflected by the objective lens 1. Image near the focal point, and the light source image 1
3'is displayed on the television monitor 19 together with the fundus image Er '. Since the light source image 13 'is generated in the visual field, it does not disappear even when the magnification is changed by the taking lens 5 and the visual field becomes narrow.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera used for photographing a fundus image in an ophthalmic hospital or the like.

[0002]

2. Description of the Related Art In a conventional fundus camera that aligns with infrared light and shoots with visible light, a photographing diaphragm is used so that a corneal reflection image for alignment is generated in the periphery of the visual field in an overlapping manner with the fundus image. There is a light source around.

[0003]

However, the above-described conventional fundus camera has the following problems. (1) When magnifying the image, the corneal reflection image is out of the field of view of the magnified image. (2) When taking peripheral images, the corneal reflection image is out of the field of view and cannot be seen. (3) Even if you try to align with visible light, you cannot see it because infrared light is used for the alignment light source. (4) Since the light splitting member is provided between the shooting diaphragm and the shooting optical system, adverse effects on the shooting optical system such as a decrease in light amount occur.

The first object of the present invention is to solve the above-mentioned problem (1).
The object of the present invention is to provide a fundus camera capable of observing the corneal reflection image and performing alignment even during magnified imaging.

The second object of the present invention is to solve the above problem (2).
The object of the present invention is to provide a fundus camera capable of aligning the corneal reflection image even when photographing the periphery.

The third object of the present invention is to solve the above-mentioned problem (3).
It is an object of the present invention to provide a fundus camera capable of performing position adjustment using a corneal reflection image for both infrared light and visible light.

The fourth object of the present invention is to solve the above problem (4).
It is an object of the present invention to provide a fundus camera capable of generating a corneal reflection image for alignment in the center of the visual field without affecting the photographing optical system.

[0008]

A fundus camera according to a first aspect of the invention for achieving the above object is a fundus camera for projecting a light flux through an objective lens onto an anterior segment of the eye and observing corneal reflected light thereof together with a fundus image. It is characterized in that a positioning light source is provided in and around the photographing aperture or at a conjugate position thereof.

A fundus camera according to a second aspect of the invention is a fundus camera which projects a light flux onto an anterior segment of an eye through an objective lens and observes corneal reflected light together with a fundus image, and a light splitting member obliquely provided in a projection optical path, A positioning light source for projecting a light beam is provided on the light splitting member, and the positioning light source is arranged on and around the optical axis of the objective lens and near a conjugate position with the photographing diaphragm.

A fundus camera according to a third aspect of the invention is a fundus camera for projecting a light flux to an anterior segment of an eye through an objective lens and observing its cornea reflected light together with a fundus image. It is characterized in that it is provided at a conjugate position.

A fundus camera according to a fourth aspect of the invention is a fundus camera for projecting a light flux to an anterior segment of an eye through an objective lens and observing the reflected light of the cornea together with a fundus image, the photographing diaphragm on the objective lens side and the projection optical system side. It is characterized in that it has a light splitting member arranged between the diaphragm and a light source for alignment that projects a light beam through the light splitting member.

[0012]

The fundus camera of the first invention having the above-mentioned structure is
Positioning light sources are provided in the imaging diaphragm and its periphery or at their conjugate positions, and the corneal reflection image of the light flux is observed together with the fundus image to perform the positioning.

In the fundus camera of the second invention, a light source for alignment is provided on and around the optical axis of the objective lens and at a conjugate position with the photographing diaphragm, and the light source is provided via a light dividing member obliquely provided in the projection optical path. The light flux is projected onto the cornea, and the corneal reflection image is observed together with the fundus image for alignment.

The fundus camera of the third invention is provided with a visible light and infrared light source in the vicinity of the photographing diaphragm or at a conjugate position thereof, and observes the corneal reflection image of the light flux together with the fundus image for alignment.

In the fundus camera of the fourth invention, a light splitting member is provided between the photographing diaphragm on the objective lens side and the diaphragm on the projection optical system side, and the light flux from the light source for alignment is directed to the cornea via the light splitting member. The projection is performed, and the corneal reflection image is observed together with the fundus image to perform alignment.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a block diagram of the first embodiment, in which an objective lens 1, a light splitting member 2, a perforated mirror 3, a photographing diaphragm 4, a photographing lens 5, and a switching lens are arranged on an optical axis O1 in front of an eye E to be examined. The mirror 6 and the film 7 are sequentially arranged. The light splitting member 2 may be fixed on the optical path by using a half mirror, or may be removed from the optical path at the time of shooting with strobe light by using a switching mirror. Further, on the optical axis O2 in the incident direction of the perforated mirror 3, a lens 8, a stroboscopic light source 9, a lens 10, a filter 11 that transmits only infrared light, and an illumination light source 12 such as a lamp are sequentially arranged. Has been done.

On the optical axis O3 in the incident direction of the light splitting member 2,
As shown in FIG. 2, the alignment light sources 13 to 16 are arranged substantially at the conjugate position with the photographing diaphragm 4 via the light splitting member 2. The light source 13 is on the optical axis O3, the light sources 14 are arranged on both sides of the light source 13, and the light sources 15 are arranged on the upper and lower sides.
15 emits near-infrared light and is mainly used for alignment during non-mydriatic photography. The light source 16 emits visible light and is used for the first alignment performed during fluorescence photography. At this time, the filter 11 is separated from the optical path in the direction of arrow P in FIG. It is possible to match.

Further, since near infrared light and visible light have different chromatic aberrations, the light sources 13 to 15 and the light source 16 are arranged with different optical path lengths on the optical axis O3. Furthermore, when the fundus illumination of the infrared light and the visible light is switched, the light source 16 and the light sources 13 to 15 may be switched and turned on in conjunction with it.

A lens 17 and a television camera 18 are arranged on the optical axis O4 in the reflection direction of the switching mirror 6.
The output of the TV camera 18 is connected to the TV monitor 19.

The light flux from the illumination light source 12 is a near infrared filter 11, a lens 10, a flash photographing light source 9, a lens 8,
Passing through a perforated mirror 3, a light splitting member 2 and an objective lens 1,
The fundus Er of the eye E to be examined is illuminated. The reflected light from the fundus Er returns through the same optical path, and the objective lens 1, the light splitting member 2, the perforated mirror 3, the photographing diaphragm 4, the photographing lens 5, the switching mirror 6,
The image is taken by the TV camera 18 through the lens 17, and the fundus image Er ′ is displayed on the TV monitor 19.

The light beams from the alignment light sources 13 to 16 are condensed by the objective lens 1 at the center between the corneal curvature center and the apex of the cornea, and these reflected lights are imaged in the vicinity of the focal position of the objective lens 1. This light source image is displayed on the television monitor 19 so as to be superimposed on the fundus image Er ', and is mainly used for alignment in the optical axis direction.

Since the light source image 13 'of the light source 13 is generated at the center of the visual field, it does not disappear even if the visual field becomes narrow when the magnification is changed by the taking lens 5. Further, since the light sources 14 and 15 are located farther from the optical axis O1 than the aperture of the photographing diaphragm 4, they are displayed in the visual field when photographing the periphery of the fundus. Further, the image of the light source 6 is displayed in the visual field at the time of center photographing.

FIG. 3 shows a second embodiment, which is a modification of the alignment system of the first embodiment, and the other parts are the same as those in FIG. Light sources 13 to 16 on the optical axis O3
The two-hole diaphragm 20 and the lens 21 are arranged between the light splitting member 2 and the light splitting member 2, and the positions of the light sources 13 to 16 in FIG.

That is, the luminous fluxes of the light sources 13 to 16 are reflected by the lens 2
An image is once formed at the position F through the first and second aperture diaphragms 20, and a thin light beam is formed thereby, so that the spot of the light source image 13 'is separated at the time of defocusing and becomes coincident at the time of focusing. Therefore, even if there is a considerable shift in the optical axis direction, the subject can clearly see this spot light. The light sources 13 to 16 may be blinked for the same purpose.

FIG. 4 shows a side view of the third embodiment, and FIG.
[FIG. 3] is a front view seen from the direction of the optical axis O1. A photographic diaphragm 22 is provided in the central hole of the perforated mirror 3 on the optical axis O1, and a diaphragm 23 is provided on the projection optical system side behind it, and a thin antireflection film is provided on one surface between the diaphragms 22 and 23. The light splitting member 24 made of a glass plate is obliquely provided. The light splitting member 24 is formed in a horizontally long shape, and extends from the opening of the photographing diaphragm 22 to both sides. The extending portion may be a total reflection mirror. Optical axis O5 in the incident direction of the light splitting member 24
A lens 25 and alignment light sources 26 and 27 are arranged on the top.

The light fluxes of the alignment light sources 26 and 27 are once imaged by the lens 25 near the light splitting member 24, and further by the objective lens 1 at the midpoint between the apex of the cornea and the center of curvature. The light flux of the light source 26 passes through the photographing diaphragm 22, and the optical axis O5
The light flux of the light source 27, which is away from, reaches the objective lens 1 through the space between the aperture of the photographing diaphragm 22 and the aperture of the perforated mirror 3.

In the third embodiment, the fundus illuminating light of the light sources 12 and 9 does not pass through the light splitting member 24 and the fundus Er is detected.
Therefore, the scattering of illumination light and the reduction of the light amount do not occur. When a multi-aperture diaphragm having a plurality of openings such as the two-hole diaphragm 20 is used, the multi-aperture diaphragm may be arranged near the lens 25 as shown in FIG. Furthermore,
Regarding the light source 27 outside the optical axis O5, the light beam is divided into the light splitting member 24.
Instead of reflecting the light onto the eye fundus Er and guiding it to the fundus Er, the optical fiber may be arranged around the diaphragm 20 and the end face of the optical fiber may be used as the light source as is conventionally done. By disposing the light splitting member 24 between the two diaphragms 22 and 23 as in the third embodiment, it is possible to guide the alignment light beam to the eye E without affecting the imaging optical system. .

[0028]

As described above, in the fundus camera according to the first aspect of the present invention, the corneal reflection image is located in the center by providing the light source for alignment in and around the photographing diaphragm or the conjugate position thereof. Therefore, even if the field of view is narrowed during magnified imaging, the examiner can visually recognize this and perform alignment at any time.

Further, the fundus camera according to the second aspect of the invention is also provided for photographing the periphery of the fundus by providing a light source for alignment at a conjugate position with the photographing diaphragm through a light dividing member obliquely provided in the photographing optical path. The examiner can visually recognize the corneal reflection image by the light flux from the periphery of the imaging diaphragm, and can perform accurate alignment.

In the fundus camera according to the third aspect of the present invention, the visible light and infrared light sources are provided in the vicinity of the photographic diaphragm or at the conjugate position thereof, so that the visible light and the infrared light can be freely switched for alignment. it can.

In the fundus camera according to the fourth aspect of the present invention, by providing a light source for alignment on the optical axis extension of the light splitting member provided between the photographing diaphragm on the objective lens side and the diaphragm on the projection optical system side, photographing is performed. Corneal reflection can be generated and aligned in the field of view without affecting the optics.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is an explanatory diagram of an arrangement of alignment light sources.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a side view of the third embodiment.

FIG. 5 is a front view.

[Explanation of symbols]

 2, 24 Light splitting member 3 Perforated mirror 4, 20, 22, 23 Aperture 6 Switching mirror 9 Strobe light source 11 Infrared filter 12 Lamp light source 13-16, 26, 27 Positioning light source 18 Television camera 19 Television monitor

Claims (4)

[Claims] 1. A fundus camera for projecting a light flux to an anterior segment of an eye through an objective lens and observing the reflected light of the cornea together with a fundus image, wherein a light source for alignment is provided in and around the photographing diaphragm or a conjugate position thereof. Fundus camera characterized by. 2. A fundus camera for projecting a light beam to an anterior segment of an eye through an objective lens and observing its cornea reflected light together with a fundus image, and a light splitting member obliquely provided in a projection optical path, and the light splitting member projecting the light beam. A fundus camera provided with a light source for alignment, and the light source for alignment is arranged on and around the optical axis of the objective lens and near a conjugate position with the imaging diaphragm. 3. A fundus camera for projecting a light flux through an objective lens onto the anterior segment of the eye and observing the cornea reflected light together with the fundus image, wherein visible light and infrared light sources are provided near a photographing diaphragm or at a conjugate position. Characteristic fundus camera. 4. A fundus camera for projecting a light flux through an objective lens onto an anterior segment of the eye and observing the reflected light of the cornea together with a fundus image, disposed between the photographing aperture on the objective lens side and the aperture on the projection optical system side. A fundus camera, comprising: the light splitting member described above; and a positioning light source that projects a light beam through the light splitting member.